Biofuel combustion from a technology point of view - MyCourses

Biofuel combustion froma technology point of view

Sonja Enestam, R&D Manager

Bioenergy and biofuels course at Aalto

8.10.2019

Contents

• Valmet in brief

• Green energy trends

• Efficient biomass combustion

• Combustibility challenges related to biomass

• Ash quality and utilization

• Recent trends and activities

8.10.2019 Biofuel combustion from a technology point of view /Enestam3

Climate change, environmental awareness and resource scarcity drive

the need to improve resource efficiency and lower emissions.

Resource efficient and clean world

Leading global developer and supplier of process technologies, automation and

services for the pulp, paper and energy industries

Key figures in 2017

Biofuel combustion from a technology point of view /Enestam4

Orders received by

business lineOrders received

EUR 3,272 million

Net sales

EUR 3,058 million

Comparable EBITA

EUR 218 million

Comparable EBITA

margin

7.1%

Employees (on Dec 31, 2017)

12,268

38%

10%21%

32%

Services

Automation

Pulp and Energy

Paper

21%

6%

46%

17%

10%

North America

South America

EMEA

China

Asia-Pacific

Orders received by area

8.10.2019

Our pulp and energy technology offering


Pulp Recovery Energy Biotechnologies

400 boilers and environmental

protection systems delivered

300 complete fiber lines and 350

recovery islands delivered

• Wood handling systems

• Cooking systems

• Complete fiber lines

• Pulp drying systems

• Evaporation systems

• Recovery islands

• Circulating fluidized bed boilers (CYMIC)

• Bubbling fluidized bed boilers (HYBEX)

• Biomass and waste gasification

• Oil and gas boilers

• Waste heat recovery

• Air pollution control systems

• Pyrolysis solutions for bio-oil production

• LignoBoost for lignin extraction

• Steam treated pellets production lines

• Biomass prehydrolysisfor further refining to fuels or chemicals

Contents

• Valmet in brief






0

200

400

600

800

1 000

1 200

1 400

1 600

2010 2011 2012 2013 2014 2015 2016

En

erg

y c

on

su

pti

on

[P

J]

Other energy sources

Hydro power

Net imports of electricity

Nuclear energy

Wind power

Peat

Natural gas

Coal

Wood fuels

Oil

Total energy consumption in Finland by sourceApproximately 67% by combustion in 2016

Ref: Tilastokeskus,

http://www.stat.fi/tup/suoluk/suoluk_energia.html#_S%C3%A4hk

%C3%B6n_tuotanto8.10.2019 Biofuel combustion from a technology point of view /Enestam7

8.10.2019 Biofuel combustion from a technology point of view /Enestam8*Preliminary

2018: 77 % combustion

of biomass

CO2 emissions in Finland 2008 by source


Tilastokeskus. 2010. Suomen kasvihuonekaasupäästöt 1990–2008.

3. korjattu painos. Tilastokeskus Katsauksia 2010/1, Ympäristö ja

luonnonvarat. 66 s.

http://tilastokeskus.fi/tup/khkinv/suominir_2010.pdf

34 % from heat and

power production

http://tilastokeskus.fi/tup/khkinv/suominir_2010.pdf

11

The trend: From coal and peat to biofuels and recycled fuels

Coal Peat

Wood chips

Forest residueRecycled fuel

Agro

8.10.2019 Biofuel combustion from a technology point of view /Enestam

From linear to circular economy

12

Linear economy Circular economy

Waste

Consumption

Distribution

Production

Resource

extraction

A circular economy aims to keep products, components and materials

in a continuing cycle instead of disposal.

Waste is minimized or eliminated for example through using side

streams in other applications, processes or even industries.

Source: European UnionBiofuel combustion from a technology point of view /Enestam8.10.2019

Contents

• Valmet in brief






The basic principle of a powerplant


Boiler technology for heat and power production

BUBBLING FLUIDIZED BED BOILER

CIRCULATING FLUIDIZED BED BOILER

15

BLACK LIQUOR RECOVERY BOILER

GRATE BOILER

PULVERIZED COAL

FIRED BOILER

Ref.: http://www.brighthubengineering.com/

Ref.: B&W Vølund

8.10.2019

Biofuel combustion from a technology point of view

/Enestam

Biofuel combustion from a technology point of view /Enestam

http://www.brighthubengineering.com/

BFB – Basic principle

16

In a BFB boiler the fuel is

introduced into a dense sand bed

which is kept fluidized by upwards

flowing fluidization gas consisting

of primary air and recirculation

gas mixture

Combustion is completed in the

upper furnace with the help of

secondary and tertiary air

Released heat is absorbed into

the water-steam cycle and steam

is then led into a turbine or other

processes

Produced flue gases are cleaned

in the flue gas cleaning system

and introduced into atmosphere

via the stack


Fluidized bed technology

BFB

Bubbling Fluidized Bed boiler

CFB

Circulating Fluidized Bed boiler


Animations/Hybex_en_highres.wmv

Fluidized Bed Combustion TechnologyThe fuel flexible solution for heterogenous fuels and fuel mixtures suchas biofuels and waste fractions

18

CYMIC CFB

• Fuel moisture range 0 - 60 %

• High steam parameters for corrosive fuels

• Low Emissions

• Coal co-combustion and backup

HYBEX BFB

• Fuel moisture range 25 – 65 %

• Steam parameters depending on fuel

• Low Emissions

• Full capacity with biofuel, waste, oil and gas

• High boiler efficiency

• >99.5% carbon burnout with

low excess air

• Low Emissions

• Fuel Flexibility

• High Reliability, typical >98 %


Fuel properties / the starting point for boiler design

Heating value

Moisture

Physical

characteristics

Ash content

Ash composition

– Cl, S, Ca, K, Na, Pb,

Zn, P…

19

• Furnace dimensions

• Air / fuel ratio

• Use of flue gas recirculation

• Fuel feeding

• HSE

• Fouling and slagging propensity

• Ash handling

• Fouling propensity

• Corrosivity

• Bed agglomeration

• Emissions

• Ash quality8.10.2019 Biofuel combustion from a technology point of view /Enestam

20

Parameters steering the fuel choiceBalancing economy and sustainability

EconomyEnvironmental regulations

-CO2 trade

-green energy benefits

Sustainability aspects

Fuel availability

Price

Fuel quality and

combustibility

-emissions

-corrosion

-ash quality

-bed sintering


Fuel cost


The production cost split of a solid

fuel fired thermal power plant.

For unit size of 80 MWfuel and

annual operating time of 8000

hours fuel cost is about 9 MEUR

(fuel price 14 €/MWh)

Fixed O&M Cost13 %

Variable O&M Cost

12 % Capital cost25 %

Fuel cost50 %

22

Fu

el p

rice

[€

/MW

h]

Level of challenge

1 5 10

The fuel dilemma

Agro biomass• Straw• Sunflowerhulls• Corn Stover• Miscanthus

Wood biomass• Northern wood • Pulp&Paper

sludges• Wood pellets

•

Recycled fuels• Packaging

waste • Recycledwood

Fast growing wood

• WillowEucalyptus •

FossilHard coal•


Fuel related challenges in a power plant

23

K2SO4

Na2SO4

K2Si4O9

Na2Si4O9

PbCl2,

ZnCl2

HCl

SO2

NOX

HCl

SO2

Pb, Zn, As, Cr, Cu, Ti,, Ba….

H2SO4

HCl

CaSO4

KCl

K2CrO4

C, H, N,

S, Cl…

HHV

LHV

H2O

CO2

N2

O2

CaCl2•H2OFuel

mixture

Emissions

Ash quality

Flue gas

cleaning

Primary

emissions

Corrosion

Corrosion

Sintering

Additives

Slagging

/FoulingAdditives


24

Typical analyses of different types of fuelsminimum – average – maximum

Peat Wood chips

Scandinavian

Bark Demolition wood

SRF AGRO(Straw, Barley)

Moisture [wt-%] 10– 45 – 65 10 – 45 – 60 0.3 – 50 – 65 5 – 10 – 30 5 – 35 – 55 5 – 10 – 20

Ash (815C)

[wt-% of ds]

2 – 6 – 18 0.2 – 1.5 – 4 0.1 – 4.0 – 13 1 – 3.5 – 13 10 – 18 – 26 4 – 6,5 – 12

HHVdry [MJ/kg] 17 – 22 – 23 19 – 21– 26 15.5 – 20 – 33 18 – 19.5 – 21 15.0 – 19.5 – 25 16.5 – 18.5 – 19

LHVwet [MJ/kg] 5 – 11 – 21,5 1.5 – 10 – 17 4.1 – 9.1 – 20.9 13 – 14.5 – 15.5 8.5 – 11 – 17 13.5 – 15 – 15,5

S[wt-% of

ds]0.1 – 0.2 – 0.8 0.01 – 0.04 – 0.09 0.01 – 0.05 – 0.2 0.01 – 0.07 – 0.15 0.1 – 0.5 – 0.7 <0.08 – 0.08 – 0.2

Cl[wt-% of

ds]0.02 – 0.04 – 0.25 <0.01 – 0.01 – 0.01 <0.01– 0.07 – 0.32 0.01 – 0.07 – 0.26 0.2 – 0.7 – 1.6 0.15– 0.3 – 1

Na[mg/kg of

ds]25 – 580 – 2500 5 – 160 – 520 5 – 380 – 1520 300 – 850 – 1800 3050 – 7800 – 12000 < 200– 240 – 1000

K[mg/kg of

ds]150 – 850 – 4200 10 – 850 – 1900 25 – 1700 – 4500 400 – 850 – 2350 2800 – 4800 – 6600

6000 – 12 000 –

22 000

Pb[mg/kg of

ds]2 – 8 – 30 <5 1 – 10 – 30 10 – 150– 650 1 – 50 – 110 < 5

Zn[mg/kg of

ds]5 – 30 – 150 30 – 35 – 40 100 – 1600 – 5800 100 – 1800 – 12000 200 – 400 – 600 30 – 35 – 40


Challenges related to combustion of bio and agricultural residues

25

➢ Bed sintering

➢ Slagging and fouling

➢ NOx emissions

Bio Agro

K

Cl

K

Cl

N

P

Si

➢ High temperature corroison ➢ High temperature corroison


Energy from biomass and waste

Efficiency and feasibility affected by:

Fuel availability and price

Fuel quality

Technical challenges

Flue gas cleaning

Ash quality and utilization


Contents

• Valmet in brief






28

Agglomeration

BFB- Basic operation principle

In a BFB boiler the fuel is introduced

into a dense sand bed which is kept

fluidized by upwards flowing

fluidization gas consisting of primary

air and recirculation gas mixture

Combustion is completed in the

upper furnace with the help of

secondary and tertiary air

29Bed bubbling Start-up

burner

Low load Full load8.10.2019 Biofuel combustion from a technology point of view /Enestam

file:///C:/User/Presentations and knowhow/2 Kurser/FPK II 2016/Lockerbie - LFO start-up burner heating the bed.MOV

file:///C:/Users/ftamsen/OneDrive - Valmet/User/Presentations and knowhow/2 Kurser/FPK II 2016/Lockerbie - initial bubbling.MOV

file:///C:/User/Presentations and knowhow/2 Kurser/FPK II 2016/Lockerbie - Low load with solid fuel .MOV

file:///C:/User/Presentations and knowhow/2 Kurser/FPK II 2016/Lockerbie - Full load with solid fuel .MOV

Agglomeration mechanism

= fuel =ash =sand

30 8.10.2019 Biofuel combustion from a technology point of view /Enestam

K SiPBed Agglomeration

Ref. D.Lindberg, Åbo Akademi University, 2013

Na

Ref. Piotrowska, Åbo Akademi

Sand

Sticky silicates

and/or

phosphates8.10.2019 Biofuel combustion from a technology point of view /Enestam31

Bed Agglomeration -> solutions

Bed temperature: < 750 °C

Bed material removal

Additives, e.g. kaolin

Inert bed material: AggloStop


33

Slagging and fouling

Fouling & slagging

34

Slagging

Fouling


35

Effects of slagging and fouling

Big pieces of slag falling down can lead to defluidization of the bed

Reduced heat transfer => Decreased efficiency of the boiler

Increased need for sootblowing (steam consumption)

Increased corrosion risk

– Without deposits usually no corrosion

– All deposits are not corrosive

Plugging of the boiler

– Unavailability

Partial plugging leads to increased flow velocity which in turn leads to

erosion

– Tube leakages

– Unavailability

Biofuel combustion from a technology point of view /Enestam8.10.2019

36

Influence of fuel composition and process conditions on slagging and fouling

Amount of ash in the fuel and composition of the ash

– Ash melting behavior => stickiness of the ash

– Condensable matter

Increased temperature => increased slagging and fouling, often

caused by increased load

Often leads to a ”snow ball” effect progressing with the flue gas flow in

the boiler

Swirls caused by the air feeding system can cause areas with high

slagging in the furnace

– CFD modelling

The fuel feeding system in combination with the air feeding can move

the combustion too high up in the furnace

– Both systems can be optimized with CFD modelling


0

10

20

30

40

50

60

70

80

90

100

500 550 600 650 700 750 800 850 900 950 1000

Temperature, oC

Am

ou

nt

of

me

lt, w

-%Melting behavior of different alkali salts

T15

T70

Ref: B-J Skrifvars

8.10.201937

Correct boiler design based on the fuel properties

– Empty pass in waste boilers

– Correct placement on heat exchangers

– Tube spacing of heat exchangers

Understanding of fuel ash properties

– Avoiding difficult fuel mixtures at high loads

– Avoiding certain fuels

Limiting the furnace temperature

– By recirculating flue gas

Furnace cleaning

– Avoiding the snow ball effect

Optimization of sootblowing

– Sufficient amount of superheaters

– Right type of superheaters

– Sufficient soot blowing, 1/d -> 1/ shift

Boiler cleaning at annual shut down

38

Avoiding slagging and fouling


39

Corrosion

Different corrosion types – BFB boilers

8.10.201940

Alkali chloride

induced corrosion

Heavy metal induced

corrosion

Dew point/ low

temperature corrosion

Erosion-

corrosion


41

Change of

material

→ Price

Fuel mixture

Boiler

availability

→ Economy

Superheater

placement

→ Design

Final steam

temperature

and pressure

→ Efficiency

The influence of corrosion on boiler technology and plant efficiency


Corrosion types and mechanisms

Alkali chloride induced corrosion; well understood and established

solutions

42

Alkali chloride induced corrosion of

the hottest superheaters

➢ Bio and waste combustion

Condensation of KCl(g)

KCl reacts with the metal

Critical temperature range:

material temperature > 450 °C


Corrosion mechanisms – alkali chloride induced corrosion

8.10.201943

Metal

Fe2O3

KCl

FeCl2

Fe2O3

KOH

Cl-

HCl

Metal

Cr2O3

KCl

MeCl2

Me2O3

Cl-

Me = Cr, Fe

K2CrO4

HCl

Fe2O3 Cr2O3


Corrosion types and mechanisms

Heavy metal induced corrosion; the main research topic during the last

10 years

44

Heavy metal induced corrosion

of cooler heating surfaces such

as primary superheaters and

furnace walls

➢Waste combustion


Pb induced corrosionCombustion of waste wood

8.10.201945

Fuel:

High

concentrations

of Pb + Cl

Pb present mostly as

chlorides

Formation of corrosive

compounds:

KPb2Cl5 and K2PbCl4

Corrosion

mechanism:

Formation of FeCl2(with low alloy steel)


Low temperature corrosion

Old problem – new understanding of the mechanisms

46

Corrosion of air preheaters

caused by hygroscopic salts

➢Bio and waste combustion

Ca

Hygroscopic chlorides in

deposits

Critical temperature

range: ~100-140 °C


Dewpoint corrosion

Dewpoint corrosion is usually caused by sulfuric acid (H2SO4), since it

has the highest dewpoint of all the acid gases in the flue gases

– Dewpoint between 120 - 180 °C with normal fuels

– Other acids condense only at temperatures below 80 °C

The concentration of condensing sulfuric acid depends on the

temperature and moisture content

– Concentration typically between 65% and 75%

– Temperature close to boiling point

Sulfuric acid condensed at dewpoint is very corrosive

Alternative corrosion mechanism: corrosion caused by hygroscopic

salts such as CaCl2, ZnCl2, NH4Cl

47 Biofuel combustion from a technology point of view /Enestam8.10.2019


A newly developed SO3

measurement method (developed by

Åbo Akademi) and recent research

results show that H2SO4 dew point

corrosion does not occur in bio mass

boilers or recovery boilers. In stead

the presence of highly corrosive

deliquescent salts has been identified.

Deliquescent salts form an electrolyte

on the tube surface -> pitting

corrosion

Exemples of deliquescent salts:

CaCl2, NH4Cl, ZnCl2

8.10.2019

Herzog, T.; Muller, W.; Spiegel, W.; Brell, J.;

Molitor, D,: Schneider, D (2012)

48

Highly deliquescent salts

Low temperature corrosion

49

Technical solutions

From fuel to stackUnderstanding the phenomena

50

Fuel

Combustion

reactions

Temperature

Gas atmosphere

Ash

Deposit

Corrosion

products

Air

Na2SO4

Material

Ash utilization

Emissions


8.10.2019

The corrosion rate is influenced by

8.10.2019Biofuel combustion from a technology point of view /Enestam51

– Flue gas composition

Tflue gas

– Flue gas temperature

– Solid and/or molten fly ash

– Deposit composition

Steel grade

Material temperature

The corrosivity of the environment

Tmat


Corrosion -> solutions

1. Superheater material and coatings

2. Steam temperature

3. Tube shields – most corrosive locations

4. Superheater location

5. Superheater design

6. Fuel mixture: Co-firing or additives

7. Gasification

52


Superheaters


Kymin Voima,Kuusankoski,Finland

Steam 269 MWth

107 kg/s114 bar541 °C

Fuels Bark, forest residue,sludge, peat, gas, oil

Start-up 2002

HYBEX boilerBubbling Fluidized Bed (BFB) technology

Biofuel combustion from a

technology point of view

/Enestam

54

HYBEX boilerBubbling Fluidized Bed (BFB) technology

Biofuel combustion from a

technology point of view

/Enestam

Furnace:

• Width 12 m

• Depth 11 m

• Height 36 m

Furnace membrane tubes 26 km

Superheater tubes 35 km

Economizer tubes 15 km

Connection tubes 2 km

Weight of pressure parts 1600 ton

55

Typical boiler materials

56

a May 2011 c Modified with Nb

Grade Category Cr Mo Ni OthersRelative

pricea

Typical use

(boiler part)

P265GH Non-alloy - - - 1.0 Eco, furnace, boiler

bank

16Mo3 Low alloy - 0.3 - 1.1 Furnace,

boiler bank

13CrMo44 Low alloy 1 0.5 - 1.8 Superheaters

10CrMo9-10 Low alloy 2.25 1 - 2.3 Superheaters

X10CrMoVNb9-1 High alloy ferritic 9 1 V, Nb 5.4 Superheaters

AISI 347 Standard stainless

steel

19 - 10 Nb 6.7 Superheaters

AISI 310 (Modc) High Cr stainless

steel

25 - 21 N, Nb 10.0 Superheaters

Incre

ased

corr

osio

nre

sis

tance


Corrosivity of alkali chlorides on two steels

57

No salt

NaCl

KCl0

20

40

60

80

100

450 500 525 550575

600

Co

rro

sio

n p

rod

uct

laye

r [µ

m]

T[C]

102 186

No salt

NaCl

KCl0

20

40

60

80

100

450 500525

550575

600

Co

rro

sio

n p

rod

uct

laye

r [µ

m]

T[C]

10CrMo9-10

AISI 347

NaCl and KCl equally corrosive on

the tube surface

Cr2O3 more protective

than Fe2O3


SteaMax Plant and fuel specific corrosion prediction


Use

- Selection of superheater materials

- Optimization of steam temperature

- Optimization of fuel mixtures and fuel

limits

- Evaluation of the corrosivity of fuels and

fuel mixtures

- Estimation of corrosion rate and

superheater life length

- Trouble shooting

Based on

- Composition of fuels and fuel mixtures

- Boiler design and superheater placement

- Valmet in-house tool for estimating corrosivity

- Empirical data from more than 1300 laboratory corrosion tests and more than 45 full

scale plants

SteaMax corrosion evaluationsR&D Expertise

58

Furnace wall corrosion and ower lay weldingTypical problem in boilers burning waste and waste wood

=> Low alloy base material over lay welded with Ni-based alloy


Corrosion -> solutions

1. Superheater material and coatings

2. Steam temperature

3. Tube shields – most corrosive locations

4. Superheater location

5. Superheater design

6. Fuel mixture: Co-firing or additives

7. Gasification

60


Tube shieldsMost corrosive locations


Superheater locationReduced concentration of gaseous, corrosive chloride in the vicinity of tube surfaces

8.10.201962

Empty pass Loop seal

superheater


Ways to minimize corrosionModification of the combustion environment

• Additives

➢ Sulphur

➢ Aluminium sulfate Al2(SO4)3

➢ Ferric sulfate Fe2(SO4)3

➢ Ammonium sulfate (NH4)2SO4

• Co-combustion

➢ Peat

➢ Coal

➢ Sludge


Corrosion management by sulphur addition

The sulphate eliminates alkali chlorides in the gas phase and

attaches to superheater surfaces forming a protective coat and

neutralize the effects of alkalichloride in the process

Sulfate decomposes at high temperature:

Fe2(SO4)3 => 2 Fe3+ + 3 SO42-

Alkali chloride reacts with sulfur trioxide or dioxide

2MCl(g,c)+ SO3(g)+ H2O (g) => M2SO4 (g,c)+ 2 HCl (g)

2MCl(g,c)+ SO2(g)+ ½ O2 (g)+ H2O (g) => M2SO4 (g,c)+ 2 HCl (g)

where M is Na or K

64

CorroStop Additives

Slow down

corrosion of

superheaters

Measures

and

remedies


Tailor made boiler design for challenging fuels

Based on decades of experience and research

Understanding of

– Fuel properties and composition

– The influence of boiler technology

– Combustion chemistry

– Ash behavior


Fuel based CFB concepts

8.10.201966

Solid Recovered

Fuel (SRF)Multifuel

Bio/MultiBiomass

Coal

Portion of SRF

50–900 MWth

Max 565 ºC

175 bar

Recycled Wood

50–250 MWth

Max 540 ºC

90 bar

FossilCoal

Coal rejects

Pet coke

50–1200 MWth

Max 565 ºC

175 bar


50–200 MWth

Max 480 ºC / 70 bar–

520 ºC / 90 bar

Replacing Fossil Fuels with Renewable Energy

➢ 140 MWth biomass gasifier

➢ Substituting coal for biomass

➢ Wood-based fuels are dried and gasified

➢ The product gas is burned in an existing

coal-fired 560 MW power boiler

➢ 25-40% of coal can be replaced with

renewable energy

➢ Existing assets utilized and power plant

life time extended

Gasification Plant

Vaskiluodon Voima, Finland

67

Climate Action of the Year in 2012

Case

CO2 savings correspond to

the emissions of a European

city with 30,000 inhabitants


Vaskiluodon Voima Oy, Vaasa, Finland

8.10.2019

Vaskiluodon Voima biomass gasification plantValmet delivery

July 2011 Modification auxiliary systems to make space

April 2012 Erection of gasifier

Aug 2012 Installation of burners in the boiler (maintenance break)

Sep 2012 Boiler operation on original fuel.

Mechanical installation ready and cold commissioning started.

Nov 2012 Hot commissioning, First gasification

Dec 2012 Operational plant

8.10.201968

Wet

biomass

PC boiler modifications

and new burners

Instrumentation,

electrification

and automation

Biomass receiving

and pre-handling

Large-scale belt dryer CFB gasifier 140

MWfuel

Product

gas

Dried

biomass


GasificationRecycled waste gasification plant for Lahti Energia Oy

69

Metso delivery: waste gasification

process, gas boiler, flue gas

cleaning system with auxiliary and

automation systems

2 gasification lines: 50 MW of

electricity and 90 MW of district heat

High-efficiency (gas boiler 121 bar,

540 C) conversion of recycled

waste to energy and reduction of

fossil fuels

Waste is turned into combustible

gas, which is cooled, cleaned and

combusted in a high-efficiency gas

boiler to produce steam for a steam

turbine


Contents

• Valmet in brief






Ash formation

8.10.2019

Bottom ashFly ash

Fly ash

from BHF/ESP

Fuel

Bed material

Additives

- Sulphur,

Sulphates

- Ammonia,

Urea

Temperature profile

Residence times

Air/oxygen levels

Additives

- Sodium bicarbonate

- Calcium hydroxide

- Activated carbon

Biofuel combustion from a technology point of view /Enestam71

Scrubber

Ash quality and utilization

> 1,3 ton ash produced in Finland annually, of this 500 000–600 000 ton is from biomass and peat

combustion

Ash can be further utilized e.g.

– As fertilizers

– asphalt filling material, in road works and excavation

– In concrete and cement industry

Ash utilization principle is that it shall not be a risk for human health or environment

Limits defined by legislation and authorities

Ash quality is defined by e.g. elemental composition, leachability and pH. Depends on fuel

composition, fuel mixtures, combustion technology and conditions, additives, flue gas cleaning

technology and additives

The most critical component of ash from woody biomass is typically Cd

Most common use in Finland at the moment are excavation and forest fertilizing


Ash utilizationOngoing research

190 MWth biomass plant => ash approx. 10 000 t/a

Disposal cost 75-95 €/t => 750 000-950 000 € /a

Disposal cost, valuable nutrient and metals and sustainability issues

are driving forces for active research in ash utilization

– Stabilization of dredging soil

– Fertilizers

– Geo-polymers

– Cement and concrete production

– Use in water purification and composting


Contents

• Valmet in brief






Finnish biomass boilers to Japan

The Fukushima accident 2011 lead to shut down of all nuclear reactors which covered

29% of Japan’s energy consumption

The shut downs lead to increase in fossil fuel usage, but the goal is to cut greenhouse

gas emissions by 26 % by 2030 relative to 2013 levels.

➢ One option is to replace coal with biomass


Customer goals

• Low OPEX with low cost biomass

• High operational boiler efficiency

and availability

Agrocultural residues in AP

76

Challenge

High temperature corrosion Moderate

Mid temperature corrosion Minor

Fouling & slagging Severe

Bed agglomeration Moderate

• Increased awareness of sustainability issues

• Pressure to decrease the use of coal => increase use of renewable fuels

• Lack of forest based biomass => interest in biobased residues and waste

utilization

• Interesting fuels e.g. residues from palm oil mills and straw

• Typically high in potassium and chlorine


Oil palm:

Empty Fuel Bunches - EFB


Ref: http://suaraindonesia-news.com


EFB fibers

Palm Kernel Shell - PKS


Turun Seudun EnergiantuotantoCYMIC boilerCirculating Fluidized Bed (CFB) technology

Jouni Kinni

April 9, 2014

8.10.201982

Turun Seudun Energiantuotanto, Naantali, Finland

Naantali Raisio Turku Kaarina

Turun Seudun Energiantuotanto (TSE) is a utility company owned by

local municipalities and Fortum

TSE provides district heating for the owner municipalities and

electricity

Turun Seudun Energiantuotanto, Naantali, FinlandCYMIC boiler


CYMIC boiler - Circulating Fluidized Bed (CFB) technology

Steam 144 / 130 kg/s

164 / 44 bar

555 / 555 C

390 MWth

Fuels: Wood biomass,

agro biomass, peat,

coal , SRF

Start-up 2017

TSE’s new power plant block Naantali 4 (NA4 CHP)

TSE’s new power plant block no 4 will

replace the 50-year-old coal-fired power

plant in Naantali

Annual production

– 900 GWh electricity

– 1,650 GWh heat

Production capacity

– 142 MW electricity

– 244 MWth heat


Naantali

Main takeaways

Biomass is a good substitute for fossil fuel

Energy from biomass = utilization of waste streams

Challenging fuels to burn efficiently with high availability

– Pay attention to Cl, K, Na, S, Ca, Pb

Main technical challenges

– Bed agglomeration

– Fouling

– Corrosion

Challenges can be handled through understanding of combustion chemistry

State of the art knowledge in Finland; exported to e.g. Asia


Biofuel combustion from a technology point of view - MyCourses

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